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far as to label the curves due to Kilgore as wrong, and pictures the possible 

 electron trajectories as shown in Fig. 14. 



One of the earliest papers to consider this newer picture of the electron 

 paths in the magnetron was published by Posthumus in 1935. This was 

 definitely a ballistic approach and hence suitable for discussing tonight. 



ELETCTRON 



, PATH 



ELECTRON 

 PATH 



Fig. 13 — Typical electron paths in a two-segment magnetron showing how electrons arrive 

 at the plate-half of lower potential (Kilgore). 



Posthumus limits his discussion to but one type of oscillation which can be 

 obtained in the split-anode magnetron. Those of you who are familiar 

 with the early literature on the magnetron will recall that two distinct types 

 of oscillations were frequently described. One type usually called "elec- 

 tronic" was found to occur under conditions when the magnetic field was just 



